HMB265H1 Lecture Notes - Lecture 20: Dosage Compensation, Covalent Bond, Insulin-Like Growth Factor 2

• School: UTSG
• Department: Human Biology
• Course: HMB265H1
• Professor: Maria Papaconstantinou

Document Summary

We can have genetically identical mice but they can have mastly different phenotypes and we know that all of the mice have the same genotype. All the phenotypic differences we see among the identical mice are due to epigenetics. Often these molecular mechanisms will act in concert with eachother. Yellow mice are at a higher risk of obesity, diabetes and tumor formation and these are caused by epigenetic effects. An iap is a retrotransposon and if its methylated, agouti is expressed under normal developmental control resulting in the normal brown colour. In this case, the cryptic promoter is silenced by the methylation. If its unmethylated, it results in constituitive extochic expression of the agouti gene, causing the yellow coat colour. This gene eexpression is in the heterozygous form, where the small a allale (cid:272)o(cid:374)tai(cid:374)s a(cid:373) (cid:373)utated a allele that does(cid:374)"t fu(cid:374)(cid:272)tio(cid:374) p(cid:396)ope(cid:396)l(cid:455) Different degrees of methylation result in variation in coat colour.